Unexpectedly High Levels of H₂O₂ Drive Sulfate Formation over the Residual Layer in Beijing

Environmental Science & Technology, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 2, 2025

Hydrogen peroxide (H2O2) plays a key role in atmospheric chemistry, but knowledge of its variation, sources, and impact on sulfate formation remains incomplete, especially the urban boundary layer aloft. Here, we conducted field campaign with measurements H2O2 related species at tower-based site (∼528 m above ground surface) Beijing spring 2022. The observed hourly concentration reached up to 21.2 ppbv an average value 3.4 ± 3.7 during entire observation period, which was higher than values from previous observations throughout world. budget revealed that two known sources (self-reaction HO2 radicals ozonolysis alkenes) could not account for significant H2O2, leading considerable unknown source strength (∼0.14–0.53 h–1) noon after sunset. Based levoglucosan signal, distribution fire points, backward trajectories, biomass burning emissions southwest (e.g., North China Plain) were found contribute greatly formation. Besides, photochemical aging PM2.5 might also have potential production noon. unexpectedly high concentrations aloft made vital contribution (0.2–1.1 μg m–3 h–1), be transported surface turbulent mixing. Our findings provide improved understanding chemistry megacity, as well

Language: Английский

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Validation of ERA5 Boundary Layer Meteorological Variables by Remote-Sensing Measurements in the Southeast China Mountains

Remote Sensing, Journal Year: 2024, Volume and Issue: 16(3), P. 548 - 548

Published: Jan. 31, 2024

Mountainous terrains are typical over southeast China, with complex and diverse topography, large terrain undulations, rich geographic features, meteorological variations. Previous studies show that ERA5 variables generally accurate respect to plains or urban agglomerations, while their applicability mountainous areas remains inconclusive. In this paper, using high-precision measurements probed by ground-based remote sensing instruments in May–July 2023 at a Shanghuang site the vertical accuracy of reanalysis datasets were comparatively evaluated. Our findings depict horizontal wind speeds data good performance compared Doppler lidar observations. quantitative terms, about 8% higher than observed values below height 400 m, above an increasing negative bias is along as altitude increases. Differing from speeds, there discrepancy between observations, deviation −150% 40%. terms thermal variables, temperature extracted consistent low troposphere. Nevertheless, systematic errors occur 2000–3000 overall presentation shows gradually increase altitude. Concerning relative humidity, general trend similar microwave radiometer, but 500 2500 m range 40% 100%. This study also reveals poorly representative requires further improvements during extreme weather events such rainstorms typhoons. particular, middle lower levels deviate strongly Given importance atmospheric thermodynamic stratifications both environmental climatic issues, results expand application China. More importantly, it provides credible reference for predictions climate modelings China region.

Language: Английский

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Machine Learning Reveals the Parameters Affecting the Gaseous Sulfuric Acid Distribution in a Coastal City: Model Construction and Interpretation

Environmental Science & Technology Letters, Journal Year: 2023, Volume and Issue: 10(11), P. 1045 - 1051

Published: April 12, 2023

Although the fundamental mechanisms of atmospheric new particle formation events are largely associated with gaseous sulfuric acid monomer (SA), parameters affecting SA generation and elimination remain unclear, especially in coastal areas where certain sulfur-containing precursors abundant. In this study, we utilized machine learning (ML) combination field observations to map link between influencing parameters. The developed random forest (RF) model performed well creating simulations an R2 0.90, significant factors were ultraviolet, methanesulfonic (MSA), SO2, condensation sink, relative humidity descending order. Among five factors, MSA served as indicator for species from marine emissions. black box ML was broken determine marginal contribution these output using partial dependence plots centered-individual conditional expectation plots. These results indicated that had a positive impact on performance RF model, co-occurring relationship observed during nocturnal period. Our findings reveal emitted environment have should be considered areas.

Language: Английский

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A new implementation of FLEXPART with Enviro-HIRLAM meteorological input, and a case study during a heavy air pollution event

Big Earth Data, Journal Year: 2024, Volume and Issue: 8(2), P. 397 - 434

Published: Feb. 23, 2024

We integrated Enviro-HIRLAM (Environment-High Resolution Limited Area Model) meteorological output into FLEXPART (FLEXible PARTicle dispersion model). A simulation requires input from a numerical weather prediction (NWP) model. The publicly available version of can utilize either ECMWF (European Centre for Medium-range Weather Forecasts) Integrated Forecast System (IFS) forecast or reanalysis NWP data, NCEP (U.S. National Center Environmental Prediction) Global (GFS) data. primary benefits using are that it runs at higher resolution and accounts aerosol effects in fields. compared backward trajectories generated with (both without effects) to GFS IFS inputs, case study heavy haze event which occurred Beijing, China November 2018. found results were considerably different when inputs. When included the NWP, there was small but noticeable difference calculated trajectories. Moreover, looking potential emission sensitivity instead simply expressing as lines, additional information, may have been missed only be inferred.

Language: Английский

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Effects of nocturnal boundary layer subsidence and long-distance transports on PM2.5 vertical profiles in the Yangtze River Delta of China measured by PM sensor on unmanned aerial vehicle and PM Lidar

Environmental Pollution, Journal Year: 2025, Volume and Issue: 371, P. 125935 - 125935

Published: Feb. 26, 2025

Language: Английский

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New Insights on the Formation of Nucleation Mode Particles in a Coastal City Based on a Machine Learning Approach

Environmental Science & Technology, Journal Year: 2023, Volume and Issue: 58(2), P. 1187 - 1198

Published: Dec. 20, 2023

Atmospheric particles have profound implications for the global climate and human health. Among them, ultrafine dominate in terms of number concentration exhibit enhanced toxic effects as a result their large total surface area. Therefore, understanding driving factors behind particle behavior is crucial. Machine learning (ML) provides promising approach handling complex relationships. In this study, three ML models were constructed on basis field observations to simulate nucleation mode (PNCN). All exhibited robust PNCN reproduction (R2 > 0.80), with random forest (RF) model excelling test data = 0.89). Multiple methods feature importance analysis revealed that ultraviolet (UV), H2SO4, low-volatility oxygenated organic molecules (LOOMs), temperature, O3 primary influencing PNCN. Bivariate partial dependency plots (PDPs) indicated during nighttime overcast conditions, presence H2SO4 LOOMs may play crucial role Additionally, integrating additional detailed information related emissions or meteorology would further enhance performance. This pilot study shows can be novel simulating atmospheric pollutants contributes better formation growth mechanisms particles.

Language: Английский

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The effect of cross-regional transport on ozone and particulate matter pollution in China: A review of methodology and current knowledge

The Science of The Total Environment, Journal Year: 2024, Volume and Issue: 947, P. 174196 - 174196

Published: June 26, 2024

China is currently one of the countries impacted by severe atmospheric ozone (O

Language: Английский

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The interactions of aerosol and planetary boundary layer over a large city in the Mongolian Plateau

The Science of The Total Environment, Journal Year: 2023, Volume and Issue: 907, P. 167985 - 167985

Published: Oct. 20, 2023

Language: Английский

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AI model to improve the mountain boundary layer height of ERA5

Atmospheric Research, Journal Year: 2024, Volume and Issue: 304, P. 107352 - 107352

Published: March 19, 2024

Language: Английский

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Shipboard Observations of Aerosol Chemical Properties Over the Western Pacific Ocean in Winter 2018

Journal of Geophysical Research Atmospheres, Journal Year: 2023, Volume and Issue: 128(22)

Published: Nov. 22, 2023

Abstract Based on a shipboard observation conducted in winter 2018, we reported the aerosol chemical properties and their differences offshore remote oceans over Western Pacific Ocean (WPO). It's found that compositions WPO have significant spatial heterogeneity due to influences of regional transport anthropogenic aerosols long‐path dust aerosols. The average concentration water soluble ions during whole sampling period followed Cl − > OC Na + Ca 2+ Mg EC K . Crustal elements (980.41 ng/m 3 ), (971.55 Al (781.16 ) were uniformly distributed area, but high proportion dominated regions. total heavy metals including Zn, Cu, Cr, Pb others originating from sources 208 along coastal region, about 10 times higher than 20.2 seas. For reconstructed components, an increase sea‐salt ranged 3% 72%, decrease black carbon, organic matter secondary inorganic salts, indicating transformation influence marine environment. rapidly increased event revealed serves as catalysts promote multi‐phase reactions. photochemical reaction rate area was mainly affected by sulfate emissions, with chlorine loss 18%, whereas it inverse excess oceans.

Language: Английский

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